Yoenis Cespedes looks like he will have plenty of tee times to choose from in October.

Any optimism that still remained in a season of enormous expectations was obliterated Thursday afternoon as the Mets crashed to their lowest point of their season with a pathetic 9-0 loss to the last-place Diamondbacks — who completed a three-game sweep of the defending National League champions at Citi Field.

The Mets dropped to .500 (57-57) for the first time since April 20 and have lost five of their past six games, along with 12 of their past 15 games at home.

Following the latest humiliation, manager Terry Collins met with the team. Then the players held another meeting, keeping the clubhouse closed for roughly half an hour.

At Collins’ one-question postgame press conference, the 67-year-old passionately ranted for nearly 3 ¹/₂ minutes, questioning how much his team actually wants to win.

Terry Collins speaks after the Mets lose to the Diamondbacks on Aug. 11.Charles Wenzelberg

“I’ll stand up and be accountable, but I know one thing: There better be a passion to come and play,” Collins said. “There’s gotta be a sense of this is what I do for a living, the people that pay to see me play are gonna see my best effort.

“Those who don’t want to get after it, I’ll find somebody else that does. In Las Vegas, there’s a whole clubhouse full of guys who want to sit in this room, and I’ll find them.”

Effort isn’t the issue, according to the players, but the veterans believed Collins’ meeting could provide a clean slate for their younger teammates, potentially overwhelmed by the mounting losses.

“We have a good group of guys that can take it and learn from it, hear it and get better and use it,” Kelly Johnson said. “That’s the point. When you have a group that pushes back and goes in different directions, that’s when things go downhill, but we don’t have that group.

“Right now we’re kind of sliding, but I don’t think it’s effort, I don’t think it’s talent. It’s just a matter of coming out and trusting ourselves and having confidence and having fun.”

During the players’ meeting, the message reiterated was that one swing can’t save the season. One person can’t stop an avalanche.

“A couple guys just spoke their mind about slowing the game down, about not worrying about trying to be the guy, trying to be the person that gets things changed,” Neil Walker said. “It’s gonna be a collective effort.”

Alejandro De Aza reacts after striking out.Charles Wenzelberg

Collectively, the Mets have gone 10-16 since the All-Star break and have gone more than a month without winning consecutive games. Collectively, they contributed to their most lopsided loss of the season Thursday.

The boos were relentless and the cheers were sarcastic, doled out indiscriminately. Noah Syndergaard wasn’t immune, failing in his attempt to play stopper as his slide from early-season superhero to mere mortal continued. Jon Niese was a one-inning punch line, allowing six runs in a game-sealing sixth-inning.

The farce was spread all around the field.

The Diamondbacks stole four bases — including an unchallenged attempt by pitcher Braden Shipley. Rene Rivera failed to connect with Syndergaard on a simple throw back to the mound. Matt Reynolds made an error at shortstop.

Shipley (2-1), making his fourth career start, easily silenced the impotent Mets’ offense, which was held to three hits through eight innings for the second straight day, never advancing past second.

“I don’t care who is not here. There are no excuses here. These are major league baseball players,” Collins said. “I don’t care where they come from. I don’t care how they got here. The names on their back and on the front of their uniforms say they’re a major league baseball player. It starts with them. When you come [here], you have a responsibility to the fans, the organization and the respect for this game to come out and grind it out.”

More losses will come again, but how soon? And how many more?

“We’re gonna get our ass beat again. Don’t ever mistake it. That’s part of the game,” Collins said. “You’re gonna get beat and you’re gonna get beat bad sometimes, but you need to pick yourself up and move on, and that’s what baseball players do.”